How to create normal texture with node setup?
Your model
Add a material to it 
Open a view and select node editor
You'll see your material initial setup
Add an image
Add an texture / image texture node and assign your image to it. Make sure to keep this node selected for the bake below
Go to the render panel
Select normal and click on "bake"




You can also bake bump maps, here is a example using a noise texture :